Print this pageThe Application of Ichnology to Facies
Characterization of a Channel-Levee 
System
in the Late Cretaceous Rosario
Formation, Baja California, Mexico
Callow, Richard *1; McIlroy, Duncan 1;
Kneller, Ben 2; Dykstra, Mason 3
(1) Department of Earth
Sciences, Louisiana State University, St John's, NF, Canada.
(2) Department of
Geology and Petroleum Geology, University of Aberdeen, Aberdeen, United
Kingdom.
(3) Department of Geology and Geological Engineering, Colorado School
of Mines, Golden, CO.
Sedimentology and ichnology of the Late Cretaceous Canyon
San Fernando channel system (Rosario Formation, Baja California) have been used
to generate an ichnofabric model that may be applied to enhance facies
characterization and improve palaeoenvironmental interpretations of subsurface
hydrocarbon reservoirs. The Canyon San Fernando system consists of
conglomerate-dominated channel axes, with individual thalwegs that may be bound
by small confined levees. Laterally away from the channel axis the system
consists of overbank/terrace environments composed of isolated conglomerate
bodies within heterolithic turbidite sediments, and a major channel-bounding
levee composed of sandstone and siltstone turbidites. This sedimentological and
ichnological model is based upon a composite lateral transect of facies from
channel-proximal to channel-distal depositional settings. Ichnofabric data
provide high resolution palaeoenvironmental information. Five ichnofabric
associations are recognised: 1) The Ophiomorpha ichnofabric association characterizes
the innermost channel terrace settings; 2) the Scolicia ichnofabric association
is typical of outer terrace and inner levee palaeoenvironments; 3) the Nereites
ichnofabric association dominates the channel-bounding levee; 4) an Ilmenichnus
ichnofabric is characteristic of bypass surfaces at the base of submarine
channels; and 5) a phycosiphoniform ichnofabric association occurs across
almost all studied depositional environments. The distribution of ichnofabrics
provide a framework for comparison with other turbidite channel systems in the
field, as well as in core. Ichnofabric analysis has the potential to be applied
to the study of other slope and basin floor depositional settings, and in
subsurface investigation of turbidite facies in hydrocarbon reservoirs.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California